Questions And Answers On Sun

Question: How long does it take Sunlight to reach the Earth?


Answer: 8.3 minutes

Explanation: Travelling at the speed of 3.00 x 10^8 m/s, it takes Sunlight 8.3 minutes to reach the Earth.

Question: Does the Sun rotate like the Planets?


Answer: Yes

Explanation: Sun at its equator takes 25 days to complete one rotation. The speed of rotation decreases as we head to the poles and here it takes the Sun 35 days for one rotation.

Question: How old is the Sun?


Answer: 4.6 Billion years

Explanation: The Sun formed 4.6 Billion years ago, when a large mass of gas generally called the Solar Nebula started collapsing on itself due to gravity and the internal pressure ignited the gasses.

Question: How far is the Sun from the Earth in Astronomical Units?


Answer: 1 AU

Explanation: The distance throughout the solar system is measured in Astronomical Units (AU). The distance from the Earth to the Sun is 1 Astronomical unit - equivalent to 1.496 x 10^8 km.

Question: What is the Sun mostly made up of?


Answer: Hydrogen and Helium

Explanation: Sun is mostly composed of Hydrogen and Helium, with smaller shares of metals and other gases. Hydrogen and Helium take up 71% and 27% of the Sun's mass respectively.

Question: Which reaction produces the energy in the Sun?


Answer: Thermonuclear Fusion

Explanation: Due to the high temperature and pressure at the core of the Sun, Hydrogen protons fuse to form Helium, releasing large amounts of energy. This process is called Thermonuclear Reaction.

Question: What type of Star is the Sun?


Answer: Yellow Dwarf

Explanation: Stars are classified into different categories based on factors like size, temperature, colour etc. Sun falls under the G-type main-sequence star or generally called the Yellow Dwarf. They are relatively small and have a temperature range between 5300 Kelvin to 6000 Kelvin. They fuse Hydrogen into Helium to generate energy.

Question: What is the colour of the Sun?


Answer: White

Explanation: The Sun is white in colour, but looks yellow or red because of the Earth's atmosphere, which acts like a prism. When the sunlight passes through the atmosphere, colours ranging from yellow to red are scattered the least. This is the reason why the Sun looks bright yellow or red.

Question: What are the atmospheric layers of the Sun?


Answer: Photosphere, Chromosphere and Solar Corona

Explanation: The Photosphere is the innermost atmospheric layer of the Sun. Solar Corona is the hottest and outermost atmospheric layer of Sun.

Question: Which is the Visible surface of the Sun?


Answer: Photosphere

Explanation: In the Photosphere layer, the energy from the Sun's interior is released as light (electromagnetic radiation). Sunspots occur in this layer.

Question: When is the Solar Corona visible?


Answer: During Total Solar Eclipse

Explanation: Corona is the uppermost layer of the Sun that extends to thousands of kilometres. Corona is normally not visible because the light from the Photosphere overpowers it. But, during a Total Solar Eclipse, the Moon blocks the Photosphere revealing a white halo around it, which is the Corona.

Question: What are the black spots on the Sun?


Answer: Sun Spots

Explanation: Beneath the Photosphere, the magnetic fields are often twisted by the Sun's varying rotational speed. The twisted magnetic fields restrict the flow of energy to some parts of the Photosphere. This creates an area which is cooler, hence appearing darker than the surrounding layer. They are known as the Sun Spots.

Question: Which Solar activity ejects plasma and magnetic field into the Space?


Answer: Coronal Mass Ejections

Explanation: The sudden realignment of the twisted magnetic fields creates an explosion that pushes out Solar Matter (Plasma) and Magnetic Field into the Space. This is called Coronal Mass Ejection (CMS) and it can be accompanied by a Solar Flare.

Question: What is a Solar Flare?


Answer: An intense burst of radiation

Explanation: A Solar Flare happens for the same reason as CMS. The sudden realignment of magnetic fields below the Solar Spots releases large amounts of energy in the form of radiation (light). Solar flares are sudden flashes that can last for several minutes to hours.

Question: What are the stream of charged particles released from Corona called?


Answer: Solar wind

Explanation: Solar Winds are a steady outflow of charged particles from the Corona. The high temperatures and the magnetic field in the Corona causes the charged particles to collide with one another, creating enough energy for the solar wind to escape the Sun's gravity.

Question: What are the large loop like structures on the Sun's surface?


Answer: Solar Prominence

Explanation: Solar Prominences are loopy gaseous structures that extend from the Sun's surface. They are again a result of the complex magnetic field in the Sun. Prominence can extend thousands of miles into the Space and are anchored to the Photosphere.

Question: What will the Sun become when there isn't enough Hydrogen in its core?


Answer: Red Giant

Explanation: Around 4.5 billion years from now, when there is no Hydrogen left at the Sun's core, the Sun will start condensing due to its own gravity. The compression will create such high temperatures that it will trigger a fusion of the hydrogen gas present in the outer layers covering the Core. This will cause the outer layer to expand into an enormous size. At this phase, the Sun will be a Red Giant.

Question: What will happen to the Sun after the Red Giant phase?


Answer: It will become a White Dwarf

Explanation: During the Red Giant phase, the mass and the temperature at the Core are so high that the Helium starts to fuse and turns into Carbon. This fusion reaction is so strong that the outer layer explodes. After the Core is out of Helium, the Sun begins to shrink and will eventually become a white dwarf. At this point, the fusion reaction at the core comes to a halt.